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H. C. LOUDENBECK.

PROCESS FOR MAKING PISTON PACKING.

APPLICATION FILED SEPT. Zh 1917.

Patented Aug. 26, 1919.

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UNITED STATES PATENT oEEIcE.

HARRY C. LOUDENBECK, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE WESTINGHOUSE AIR BRAKE COMPANY, OF WILMERDING, PENNSYLVANIA,

A. CORPORATION OF PENNSYLVANIA.

Specification of Letters Patent.

Patented Aug. 26, 1919.

Application filed September 21, 1917. Serial No. 192,485.

To all whom it may concern:

Be it known that I, HARRY C. LOUDEN- BECK, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented new and useful Improvements in Processes for Making Piston-Packing, of which the following is a specification.

This invention relates to a process for making piston packing, more particularly of the cupped type.

Leather has heretofore been employed in the manufacture of cupped piston packing, but by reason of the increasing cost and scarcity of leather, it is highly desirable to provide packing of other material.

It is therefore proposed to employ ground cork for this purpose and in my co-pending application Serial No.192,5l0, filed Sep tember 21, 1917, is described a piston packing formed of disks of ground cord with an intermediate layer of fabric.

The principal object of the present invention is to provide a process for making cupped iston packing of the above character, W ereby the resulting packing will have resiliency to maintain contact with the cylinder walls without the use of expander rings and whereby the packing can be formed Without breaking or being excessively strained in forming.

In the accompanying drawing; Figure 1 is a sectional view of the ground cork and fabric disks employed in making the piston packing; Fig. 2 a similar v1ew of the ground cork and fabric disks in position ready for forming into packing; Fig. 3 a fragmentary sectional view of a portion of the formed packing; and Fig. 4 a sectional View of the forming die mold, showing a formed packing therein.

According to my invention, there are provided disks 1 cut from sheets formed of ground cork mixed with a suitable binder and then pressed and disks 2 cut from fabric, preferably duck or canvas.

The ound cork disks are coated on one side with glue and the fabric disks are coated on both sides with glue and a fabric disk is placed between two ground cork disks, as shown in Fig. 2. The combined disks are then placed in a die mold and formed up.

The die mold may comprise, as shown in Fig. 4; of the drawing, a base member 3, an interior moving member 1, and an interior moving member 5. The ground cork and fabric structure is placed in position on the base member 3 while the glue is still unset and by means of a suitable press, the member 41 is first brought into engagement with the packing material. The exterior member 5 is then moved to cup the packing, finally assuming the position shown in Fig. 4. While under pressure exerted by the press, a nut 6 is applied to the stud 7 secured in the base member 3 and said nut is screwed down so as to hold the packin material clamped between the base mem cr 3 and the member 4. The exterior member 5 is held in position by meansof set screws 8 which are then screwed into engagement with an annular recess9 formed in the member 4.

It will now be noted that in the cupping of the packing material, the layers of ground cork and fabric can slide on each. other, so that the material will not be subjected to excessive internal and external strains by the cupping operation.

If disks of the same diameter are used, the outer edges of the disks will assume the relative positions, as shown in Fig. 3, since the bending of the outer layers requires more material due to the larger bending radius. This also serves to indicate how in the formation of packing without sliding layers,

excessive strains are introduced, since it will be evident that the outer portion at the bend must either stretch or break to accommodate the larger bending radius.

After the parts of the die mold are locked together as hereinbefore described, the die mold containing the packing is heat treated to render insoluble and set the glue, the glue being preferably of such character that heating makes the same insoluble and therefore water and oil proof.

The packing is then removed from the mold and is now ready for service.

Having now described my invention, what I claim as new and desire to secure by Lettors Patent, is

1. The process of forming cupped piston packing which consists in coating disks of ground cork with glue, superimposing said disks, and then pressing the superimposed disks from a flat condition into the cup form while the glue remains unset.

2. The process of forming cupped piston packing which consists in providing disks of pressed ground cork mixed with a suitable binder, applying glue to one side of the disks, then forming piles of two ground cork disks with an intermediate layer of fabric, and in then pressing the pile from a fiat condition into the cup shape while the glue remains unset.

3. The process of forming cupped piston packing which consists in providing disks of pressed ground cork, coating said disks with glue, forming a flat pile of two ground cork disks with an intermediate layer of fabric, then pressing the pile into cup shape by means of a die mold, while the glue remains unset, and in then subjecting the die mold with the included packing to heat, for setting the glue and rendering the same insoluble. v

In testimony whereof I have hereunto set my hand.

HARRY C. LOUDENBECK. 

